Not sure about the Rns510 but the Rcd510 drains the battery on my o5 gti . Turns out the older can gateway (1k0907530F) in my car cannot communicate properly with the Rcd510 . As a result the cars electrical system does not go into hibernate mode, after a defined period, once car has been switched off . This in turn leads to a flat battery after about two days without use. The apparent fix is to change, as mentioned in above post , the can gateway to the latest version 1k0907530S.
As a short term fix to the battery drain try pulling the fuse for the radio when the car is left unused overnight. Besides the hassle of popping the bonnet to do this & the radio going through a cold reset each time you replace the fuse i.e cycles through the inbuilt six cds it has stopped the battery drain.
I tried to locate the can gateway today , using a post/pictures from another site, but failed . The pictures were from a LHD car which had the part located near the accelerator pedal , but I couldn't find it
Anybody know where the can gateway resides on a RHD car ?????